Children who are spanked are more likely to be aggressive, defy their parents, and exhibit anti-social behavior, a meta-analysis found, based on 50 years of research by experts at the University of Michigan and the University of Texas at Austin. According to Science Daily, the researchers say it is the most complete analysis on the effects of spanking, as it took place over 5 decades and included 160,000 children.

The study was published in this month's issue of the Journal of Family Psychology, and makes clear that researchers focused on spanking only, "defined as an open-handed hit on the behind or extremities," the study notes, and not on other forms of physical punishment that could be considered abusive.

Elizabeth Gershoff, associate professor of human development and family sciences at The University of Texas at Austin, said in the study "We found that spanking was associated with unintended detrimental outcomes and was not associated with more immediate or long-term compliance, which are parents' intended outcomes when they discipline their children."

Rather than enforcing good behavior, the more often children were spanked, the more likely they were to be anti-social and suffer from mental health issues. They were also likely to support spanking as a form of discipline for their own children, which demonstrates how feelings toward physical punishment are passed down from one generation to the next.

According to a 2014 UNICEF report, as much as 80 percent of parents across the globe spank their children, despite the lack of evidence for any type of positive outcome, and the mounting evidence of negative outcomes on a child's behavior and development. In fact, this most recent research shows that spanking is linked to the same type of negative outcomes in a child as physical abuse, but to a slightly lesser degree.

Gershoff hopes this research will help decrease physical forms of punishment for children. "We hope that our study can help educate parents about the potential harms of spanking and prompt them to try positive and non-punitive forms of discipline," she said.